Lithifying microbial mats are complex ecosystems that facilitate the trapping and binding of sediments and/or the precipitation of calcium carbonate into organo-sedimentary structures known as microbialites. And because of their significance, Ahrendt et al. (2014) examined the effects that a tripling of the atmosphere's CO2 concentration might have on the mats, which they did within growth chambers they constructed that could continually manipulate and monitor microbial mat environments. And what did they thereby learn?

The five U.S. scientists report that "elevated CO2 levels during the six-month exposure did not profoundly alter the microbial diversity, community structure, or carbonate precipitation in the microbial mats." However, they say that "some key taxa, such as the sulfate-reducing bacteria Deltasulfobacterales, were enriched." And they thus go on to conclude that their results suggest that "some carbonate depositing ecosystems, such as the microbialites, may be more resilient to anthropogenic-induced environmental change than previously thought."